This invention relates to an ink jet recording apparatus having a capping mechanism for capping ink jet nozzles, and more particularly to an ink jet recording apparatus having a capping mechanism which caps ink jet nozzles by pushing a cap against the nozzle surface by the elastic force of a spring or the like.
A detailed explanation will be given of the conventional ink jet head capping device.
FIG. 4 shows in simplified form the capping mechanism of a conventional ink jet recording apparatus. A gear 2 is rotated by receiving a driving force from a motor 1, and transfers the rotating force to a rotary cam 4 via a rotary shaft 3. Arm 4 produces a rocking movement of a cap supporting arm 6 about an axis 6'. The rotary cam 4 is connected to rotary shaft 3 via a torque transmitting spring, and is able to put on or draw off an ink jet head cap 7 by means of the forward or reverse rotation of motor 1.
During a time when printing is stopped, the ink jet head unit 8 is slid along ink jet head supporting shafts 13, in a direction perpendicular to the plane of FIG. 4 to stop at the capping position above the ink jet head capping device. Rotary cam 4 is then rotated by motor 1 in the forward direction (in the direction of the arrow of FIG. 4) until rotary cam 4 moves out of contact with head cap supporting arm 6. Then, head cap supporting arm 6 is pivoted by spring 11 to raise head cap 7 into the capping position.
At the time of head cleaning, motor 1 continues forward rotation, and a cleaning pump driven by the rotation of gear 2 effects suction performance. During this time, rotary cam 4 stops rotation and rotary shaft 3 continues rotating, by the function of the transmitting spring.
At the time when cap 7 is to be removed, rotary cam 4 is rotated in the reverse direction by motor 1 and is touched to the head cap supporting arm 6 to pull down the ink jet head cap 7 and place it in the open state.
As described above, at the time of stopped printing or head cleaning, the elastic force of the spring 11 maintains the capping state.
In the case of the conventional example as described above, there are the advantages that the cost is low and miniaturization is possible. However, in the conventional case where single colored copying was the main trend, since miniaturization of the head was possible, the capping state could be maintained for the oscillation in the time of transference by the elastic force of an elastic material such as a spring. However, in the case of multi-color copying, which is increasingly in demand, there is a limit in the miniaturization of the head due to the multi-nozzle formation required for this type of copying.
Corresponding to the large size of the head, the head capping device also has come to be formed in a large size.
In the case of capping devices of large size such as described above, it is difficult to maintain the capping state, and due to the oscillation at the time of transference, the ink jet caps oscillate, together with shrinkage of the maintaining elastic material, and there are generated such drawbacks as the clogging of the head due to the leakage of ink and intrusion of dust, damage to the device due to the shock of the oscillation, and the like.